Water purification system

ABSTRACT

A water purification system utilizes a radial filter and an ultraviolet lamp in a small, portable, countertop housing. A standpipe is positioned between the filter and the ultraviolet lamp to control the flow of water so that it flows along substantially the entire length of the UV lamp. The lamp is made integral with a quartz-tube covering and a threaded cap and connector to enable replacement of the UV lamp assembly. The housing encompassing the filter system is also easily disassembled to enable cleaning of the housing and replacement of the filter. A pressure vent is provided in the housing cover to equalize pressure and provide for a water level differential when the filter is disabled. A UV lamp indicator is included to show that the lamp is in operation.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to water purification systems and, moreparticularly, to water purification systems using filtration andultraviolet radiation apparatus to purify the water.

2. Description of the Prior Art

It is known to use ultraviolet (UV) radiation to disinfect drinkingwater. The United States Department of Health, Education and WelfarePublic Health Service recognizes that ultraviolet radiation is a meansfor meeting the bacteriological requirements of the Public HealthService Drinking Water Standards. Studies have indicated thatultraviolet radiation at a level of 2,537 Angstrom units applied at aminimum dosage of 16,000 micro-watt-seconds per square centimeter at allpoints throughout a water disinfection chamber is adequate to purifywater for drinking. Industry has set its own standard of 30,000micro-watt-seconds to account for any losses that may occur in thechamber. If one uses a UV lamp that has a guarantee of maintaining 80%power over 9,000 hours (one year) then setting a standard of 38,000micro-watt-seconds per square centimeter would insure that the lampwould require replacement no more than yearly, while adequatelysterilizing water flow exposed to the UV lamp.

Many rural areas in the United States and throughout the world do nothave high water pressure and do not have a reliable water source. Forinstance, people who depend on cisterns or well water may have goodwater today and contaminated water tomorrow. Many of these systems usegravity as the source of water pressure or have well pumps that are onlya slight improvement.

In U.S. Pat. No. 4,968,437 to Electrolux a sterilization system employstwo plastic tubes at least six feet in length having a cross-sectionalarea of about 0.2 square inches. The tubes are wrapped spirally,interleaved around an ultraviolet-light-producing lamp, and connected inseries with a filter between them. The apparatus disclosed in theElectrolux '437 patent may be suitable for some applications, but thereare applications where it is not practical.

First, if the water being treated is turbid the first plastic tube willbe ineffective because there is no pre-filter. The UV light will not beable to pass through the water and will not be entirely effective indestroying all microorganisms. Moreover, because there is no pre-filter,material passing through the first plastic tube can accumulate on theinside surface of the tube. The accumulation can render the first tubeineffective over time by restricting the transmittance of the UVradiation through the tube. This would require frequent inspection andcleaning/replacement of the tube system.

In addition, the transmission characteristics of plastic for ultravioletradiation are significantly lower than those of quartz or high-silicaglass recommended by the U.S. Public Health Service. Thus, theultraviolet lamp would need to be quite large to overcome the lossesbuilt into the system. The absorption of the UV radiation by the plasticis called solarization and becomes worse as the plastic ages, producingdarkening of the material and increasing the absorption rate of UVradiation.

Another problem with an Electrolux-type system is that the water musttravel through at least 12 feet of tubing which is approximately 0.2inches in cross-sectional area, causing significant losses in waterpressure. The filter adds to the pressure losses so that the flow ratewould likely drop to a point that makes the unit undesirable for lowpressure applications. Moreover, the size of the Electrolux '437 unitand hookup method make it impractical for a counter-top unit.

Another prior art system shown in FIG. 1 utilizes a radial-flow carboncartridge and a ultraviolet lamp in the center. In this system, thewater can flow at any point along the carbon cartridge into proximitywith the ultraviolet lamp and then to the output. Thus, the flow of atleast part of the water can substantially bypass the ultraviolet lamp ator near the input to the filter, thereby contaminating the water flowingout of the filter.

As shown in FIG. 1, the water enters at input port 1 and fills up thehousing. It then travels through the filter 2 and passes the ultravioletlamp 3 before exiting at output port 4. Because the water will take thepath of least resistance, some of it will cross the filter 2 at the topand have a shorter path past the ultraviolet lamp 3 to the exit port 4.

Another problem with this prior art filter is that the ultraviolet lightis radiated directly on the plastic housing of the filter medium. Bycontinued exposure to UV light, the plastic housing will break down andrelease some of its component material into the water.

SUMMARY OF THE INVENTION

The present invention provides a countertop water filter system that iseffective for low pressure systems as well as for normal pressuresystems common in most households. This system provides high-quality,purified, potable water which is substantially free of all livingmicroorganisms. This system of the present invention is modular, withthe capability to be expanded and/or modified to meet the specific needsof the user.

The system of the present invention has simple maintenance procedureswhich keeps the overall cost of system operation low. This unit isrelatively small and portable. Maintenance can be done on a regularbasis by a layman without a technician's assistance. The present systemcan also be installed by a layman and does not require the services of aplumber or electrician. Installation is accomplished by removing theaerator from the sink faucet and replacing it with an diverter/aeratorhaving a tube which connects to the filter system. The system is hookedup electrically by connecting the four-pin plug on top of the unit withthe plug on the end of the ballast cable. The ballast is then pluggedinto a wall outlet in the same manner that most countertop appliancesare connected.

In one preferred form of the present invention, the water purificationsystem comprises an enclosed housing assembly having a base with inletand outlet ports for water flow. A standpipe is disposed in the baseover the outlet port. A radial filter is disposed circumferentiallyaround the standpipe and is sealed by a housing cover to the ends of thefilter to prevent water from bypassing the filter. An ultraviolet lampassembly is connected to the top of the cover and extends through thecenter of the standpipe. A vent check valve is installed in the top ofthe cover. A faucet is screwed on the base at the output port.

Another alternate embodiment of the present invention provides for dualmodules as described above connected in a series. Yet another embodimentprovides for one unit described above connected in tandem with apost-filter module not having the ultraviolet lamp assembly. Anotherembodiment of the present invention includes a pre-filter attached inseries to the filter module described above.

In operation, the diverter/aerator is selected to the filter afterturning on the water faucet. The water enters the filter housing andpasses through the filter medium where particulate matter and unwantedchemicals are removed. As the housing fills up, the water reaches thelevel of the standpipe and overflows. The overflowing water passes alongthe entire length of the ultraviolet lamp where it is radiated with highintensity ultraviolet light, killing the microorganisms present in thewater. The water then flows up and out of the purifier faucet forconsumption. When the water is shut off, the housing vents to theatmosphere through the vent check valve. The water level in the housingdrops to the top of the standpipe, and the water level in the standpipedrops to the level of the top of the output faucet. This difference inwater levels provides a barrier between the untreated water and treatedwater. If power to the system is lost, the integrity of the systemagainst microorganisms is maintained by this barrier.

The pre-filter in the present system eliminates turbidity of the waterand keeps the ultraviolet lamp assembly clean. The clear water does notrestrict the transmittance of the ultraviolet radiation. By keeping thewater clean the UV lamp remains clean longer, thus operating at topradiation efficiency. The present invention utilizes a quartz,high-silica tube encasing the UV lamp to maintain its clarity throughoutthe lifetime of the lamp, reduce solarizing, and keep the ultravioletradiation at peak efficiency. By allowing the water to flow around thetotal circumference of the UV lamp at the same time, back pressure iskept to a minimum, enabling use of unit at low pressures. The small sizeof the unit and ease of hookup enable the use of the filter of thepresent invention for countertop and portable applications.

The modularity of the present system enables it to be modified to meetthe needs of specific users. For instance, if lead in the water is anadditional problem, the filter media can be changed to accommodate theproblem. If the flow rate needs to be increased, additional units can beconnected in series.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cutaway view of a prior art ultraviolet filter system;

FIG. 2 shows a system of the present invention hooked up to a householdfaucet and power outlet;

FIG. 3 is a cutaway view of the filter system of the present inventionshowing the flow path of the water;

FIG. 4 is a cutaway view of the base and standpipe of the filter systemshown in FIG. 3;

FIG. 5 is a cutaway view of an alternate configuration of thefilter/sterilization system of the present invention, having twoultraviolet modules in series;

FIG. 6 is a cutaway view of an alternate configuration of the filtersystem of the present invention having an ultraviolet module in serieswith a post-filter module; and

FIG. 7 is a cutaway view of an alternate configuration of the filtersystem of the present invention having a pre-filter module in serieswith an ultraviolet module.

DETAILED DESCRIPTION

FIG. 2 shows the hookup of one preferred embodiment of the waterpurification system. The system is small and portable, and it fitseasily on most counter tops. The diverter/aerator 6 is connected to thesink faucet in place of the standard aerator. A tube 7 connects thediverter/aerator 6 to the base of the housing 16 of filter assembly 14.A cord 30 for the power supply plugs into a conventional electricaloutlet.

Referring to FIG. 3, the housing 16 of filter assembly 14 includes abase 18 having an input water port 8 and an output water port 12. Astandpipe 10 is installed in the center of the base 18 over an orifice28 leading to the outlet port 12, as also shown in FIG. 4. The radialfilter 9 is disposed concentrically around the standpipe 10. The cover17 has a female-threaded flange 26 which screws on to a male-threadedportion 27 of base 18. Circular rings 20 and 21 impinge against rubberseals 22 and 23 to clamp and seal the ends of the filter 9 to preventwater from bypassing the filter.

The ultraviolet lamp assembly 11 includes an ultraviolet lamp 32connected to a power cord 30. A clear tube 33, having a diameterslightly larger than lamp 32, concentrically surrounds lamp 32. Theupper end of tube 33 extends through a hollow threaded connector 25 andis secured thereto by an adhesive. Connector 25 extends through athreaded opening in top 24 and terminates in a threaded cap 31. Twoholes are drilled in cap 31, one for power cable 30 running to connector19, and the other hole for the UV power indicator 15. Lamp assembly 11is thus connected in the top 24 of the cover 17 so that the assemblyextends down the center of standpipe 10. A vent check valve 29 isinstalled in the top 24 of the cover. A faucet 13 is screwed on the baseat the output port.

The standpipe 10 prevents the water from bypassing the ultraviolet lampassembly 11 or taking a shortcut as in the prior art (See FIG. 1). Thestandpipe 10 is preferably made of teflon or metal such as, but notlimited to, copper or stainless steel to prevent the breakdown thatoccurs from exposure of other materials to ultraviolet radiation.Alternately, standpipe 10 may be made of plastic and coated with metal.A secondary purpose of the standpipe is to shield the filter from theultraviolet radiation. The plastic webbing material covering the filterwill break down with extended exposure to high intensity UV radiation,thus releasing potentially harmful component materials into the water.

As shown in FIGS. 2 and 3, the water that is diverted from the sinkfaucet passes through the tubing 7 and enters the housing at the inputport 8. The water rises in the housing and passes through the filtermedium 9, removing undesirable particulate matter and chemicals. Thefiltered water then rises to the top of the standpipe 10 and flows downtoward the output orifice 28. With the ultraviolet lamp assembly 11 inthe center of the standpipe 10, the filtered water is exposed to maximumradiation for the full length of the standpipe thereby destroying theliving microorganisms in the water. The purified water exits the housingat the output port 12 and passes through the faucet 13.

When the water supply is turned off, the housing assembly is vented tothe atmosphere through vent check valve 29. This vent equalizes thepressures inside the housing and allows the water inside to drainthrough the faucet 13. The water level inside the housing will dropuntil it reaches the top of the standpipe 10. This water level insidethe standpipe 10 will continue to drop until it reaches the same levelas the top of the faucet 13. This separation divides the sterilized andunsterilized water and prevents contamination of the output port and thefaucet in the event of a power outage.

The tube 33 which covers and protects the ultraviolet lamp 32 ispreferably a conventional quartz tube. The UV power indicator 15 is madeof a translucent piece of plastic that radiates the reflected light fromthe UV lamp. Vent check valve 29 is preferably a conventional unit, suchas model number A627 made by Miniature Precision Components located inWalworth, Wis.

The UV lamp 32 is preferably a conventional unit, model number GPH212T5Lmade by Light Sources, Inc. of Milford, Conn. and modified as shown. Theactivated carbon filter 9 is preferably a conventional unit such asmodel number S1035-1 made by Clack, Inc. of Windsor, Wis. The housingassembly, including the cover and base, is preferably a plastic unitcalled Hydro-Cure Housing made by Clack, Inc. and modified as shown.

Two types of maintenance activities are required for this system. One isreplacement of the ultraviolet lamp assembly 11 and the other is thereplacement of the filter medium 9 and cleaning of the system. Forreplacement of the ultraviolet lamp assembly 11, the power connector 19is disconnected from the ballast cable 30 and the assembly 11 isunscrewed from the top 24 of the housing cover 17. The cap 31, lamp 32,and quartz tube 33 are integrally formed as one assembly to reduce thepossibility of breaking fragile components such as the ultraviolet lamp.After removal of the old lamp assembly 11, the new part is removed fromthe package, inserted through the opening in the top 24 of the housingcover 17 and screwed in. The power connector 19 is then plugged into theballast cable 30 and the unit is ready for operation.

For replacement of the filter and for cleaning the unit, the ultravioletlamp assembly 11 is removed as described above and the housing assembly16 is placed horizontally over the sink. The housing cover 17 isunscrewed from the base 18 and set aside. The old filter 9 is lifted offfrom over the standpipe 10 and is discarded. The inside of the filterhousing cover 17 is washed with a mild detergent and the standpipe 10 iscleaned with a bottle brush. Upon completion of cleaning the standpipe10, a disinfecting solution is poured through to insure that the exitport 12 and the faucet 13 remain uncontaminated. The replacement filter9 is then installed over the standpipe 10 and the housing cover 17 isthen screwed on to base 18. The ultraviolet lamp assembly 11 is thenreinstalled as described above.

Another embodiment of the filter of the present invention appears inFIG. 5 in which two filter units 40 and 42 are connected in series. Eachunit 40 and 42 are identical to the filter system 14 shown in FIG. 3. Byconnecting the units in series, the amount of ultraviolet radiation isdoubled, thus allowing the flow rate to be increased by a factor of two.At the same time, different types of filters may be used to treatdifferent problems. For instance, the first filter may be for leadremoval while the second could be for odor and taste.

Another embodiment shown in FIG. 6 utilizes one assembly 50 identical tofilter assembly 14 and a second unit 52 connected in series withassembly 50 and identical to filter assembly 14 except it does not havea UV lamp assembly 11 or a standpipe 10. This approach allows twoseparate filter problems such as those described above to be addressedwhile minimizing costs by using only one ultraviolet lamp.

Yet another embodiment is shown in FIG. 7 which also provides for twounits in tandem. The first unit 60 is a pre-filter assembly without theultraviolet lamp assembly, identical to unit 52. The second unit 62 isidentical to filter assembly 14. It is likely to be most useful insituations where the water requires extra filtering in order to make thewater pure enough to expose to UV light.

It is understood that the present invention is not limited to theembodiments described above. Various other changes and modifications maybe made by one skilled in the art without departing from the scope orspirit of the present invention.

What is claimed is:
 1. A water filter system comprising:(a) a housingassembly having an inlet port and an outlet port for directing waterflow through the housing; (b) a filter disposed in the housing betweenthe inlet port and the outlet port; (c) an ultraviolet lamp disposed inthe housing between the filter and the outlet port; (d) shield meansbetween the filter and the ultraviolet lamp for channeling the waterflow adjacent substantially the entire length of the lamp and forshielding the filter from ultraviolet radiation; and (e) a venting meansin the housing assembly to equalize pressure therein for separating thetreated water from the untreated water within the housing when the waterflow through the housing stops.
 2. The filter system of claim 1 whereinthe channeling means comprises a pipe extending adjacent to the lamp. 3.The filter system of claim 2 wherein the pipe is tubular-shaped andconcentrically surrounds the lamp.
 4. The filter system of claim 1wherein the filter is tubular-shaped and concentrically surrounds thelamp and the channeling means.
 5. The filter system of claim 1 andfurther comprising a clear casing substantially surrounding the lampdisposed between the lamp and the channeling means.
 6. The filter systemof claim 1 and further including seal means between the housing and thefilter to force the water flow from the inlet port through the filter.7. The filter system of claim 1 and further comprising indicator meansin the housing for displaying an indication that the ultraviolet lamp isactivated.
 8. The filter system of claim 1 and further comprising meansfor connecting the lamp to the housing.
 9. The filter system of claim 1wherein the filter is tubular-shaped and concentrically encompasses thechanneling means, and the channeling means is tubular-shaped andconcentrically encompasses the lamp.
 10. A water purification systemcomprising:(a) an elongated, hollow housing having a water inlet portand a water outlet port; (b) a tubular-shaped filter disposed within thehousing; (c) a tubular-shaped pipe disposed within the filter; (d) atubular-shaped ultraviolet lamp disposed within the pipe so that thepipe runs substantially the entire length of the lamp, (e) the pipebeing closed at a first end and being open at a second end to enablewater flow to pass through the second end and adjacent to the length ofthe lamp, the pipe being impervious to ultraviolet radiation to shieldthe filter therefrom; and (f) venting means in the housing assembly toequalize pressure therein for separating the treated water from theuntreated water within the housing, so that when the water flow throughthe water inlet port stops, the water level in the pipe drops below theopen end of the pipe.
 11. The water purification system of claim 10wherein the first end of the pipe is closest to the outlet port and thesecond end of the pipe is remote from the outlet port, so that the waterflow through the second end of the pipe flows substantially the entirelength of the lamp.
 12. The water purification system of claim 10wherein the filter is in sealed connection with the housing at both endsof the filter so that the water flow into the housing is forced throughthe filter.
 13. The water purification system of claim 10 and furthercomprising a quartz tube shielding substantially the entire length ofthe lamp.
 14. The water purification system of claim 10 wherein thesystem is portable and adapted to be disposed on a countertop with theinlet port being adapted for connection to a faucet diverter and theoutlet port being adapted for connection to a faucet.
 15. The waterpurification system of claim 10 and further comprising a second waterpurification system connected in tandem to the first system so that theoutlet port of the first system is connected to the inlet port of thesecond system.
 16. The water purification system of claim 15 wherein thesecond system is identical to the first system.
 17. The waterpurification system of claim 15 wherein the second system is a filterunit which has only a tubular filter therein.
 18. The water purificationsystem of claim 15 wherein the first and second system are reversed inorder so that the water flow goes first through the filter unit and thenthrough the system having an ultraviolet lamp therein.
 19. A waterfilter system comprising:(a) a housing assembly having an inlet port andan outlet port in the base of the housing for directing water flowthrough the housing, the outlet port being in communication with anoutlet faucet; (b) a replaceable filter disposed in the housing betweenthe inlet port and the outlet port; (c) an ultraviolet lamp disposed inthe housing between the filter and the outlet port; (d) pipe meansattached to the base of the housing assembly, disposed between thefilter and the ultraviolet lamp and having an opening at the top of thepipe means for channeling the water flow adjacent substantially theentire length of the lamp, and (e) a vent in the housing assembly toequalize pressure therein for separating the treated water from theuntreated water within the housing, so that when the water flow throughthe inlet port stops, the water level in the pipe means drops to thelevel of the outlet faucet.